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631.
Yanjie Xu Yali Si John Takekawa Qiang Liu Herbert H. T. Prins Shenglai Yin Diann J. Prosser Peng Gong Willem F. de Boer 《Conservation biology》2020,34(2):416-426
Habitat loss can trigger migration network collapse by isolating migratory bird breeding grounds from nonbreeding grounds. Theoretically, habitat loss can have vastly different impacts depending on the site's importance within the migratory corridor. However, migration-network connectivity and the impacts of site loss are not completely understood. We used GPS tracking data on 4 bird species in the Asian flyways to construct migration networks and proposed a framework for assessing network connectivity for migratory species. We used a node-removal process to identify stopover sites with the highest impact on connectivity. In general, migration networks with fewer stopover sites were more vulnerable to habitat loss. Node removal in order from the highest to lowest degree of habitat loss yielded an increase of network resistance similar to random removal. In contrast, resistance increased more rapidly when removing nodes in order from the highest to lowest betweenness value (quantified by the number of shortest paths passing through the specific node). We quantified the risk of migration network collapse and identified crucial sites by first selecting sites with large contributions to network connectivity and then identifying which of those sites were likely to be removed from the network (i.e., sites with habitat loss). Among these crucial sites, 42% were not designated as protected areas. Setting priorities for site protection should account for a site's position in the migration network, rather than only site-specific characteristics. Our framework for assessing migration-network connectivity enables site prioritization for conservation of migratory species. 相似文献
632.
Quan Yuan Hui Gong Hao Xi Kaijun Wang 《Frontiers of Environmental Science & Engineering》2020,14(3):49
633.
大辽河流域土壤中微塑料的丰度与分布研究 总被引:2,自引:0,他引:2
微塑料在海洋生态系统中的分布特征已有不少研究,但人类活动强度较大的流域土壤中微塑料的污染研究仍存在较大空白。以大辽河流域为研究对象,采集附近8个土壤样品,采用密度浮选法,结合体视显微镜及显微红外光谱(μ-FTIR),进行了大辽河流域土壤中微塑料的组成及分布特征研究。结果表明,土壤中微塑料颜色以白、蓝和绿色为主(88.03%),形状以碎片、薄膜和泡沫为主(总占比为96.32%),土壤中粒径为500~1 000μm的微塑料最多(41.10%),其次依次为1 000~2 000μm(26.38%)、100~500μm(19.33%)和2 000~5 000μm(11.66%)。粒径为0~100μm的微塑料和>5 000μm的塑料碎片所占比例最小(均小于1.00%)。薄膜类和碎片类微塑料的主要成分分别是聚乙烯(PE)和聚丙烯(PP),颗粒类和泡沫类的主要成分是聚苯乙烯(PS),纤维类微塑料的主要成分是聚酰胺(PA)。土壤中微塑料平均丰度为(273.33±327.65)个·kg~(-1)。总体上,该研究区域土壤中微塑料的污染程度处于中等偏低水平。 相似文献
634.
Bin Zhu Lei Liu Yu-Xin Gong Fei Ling Gao-Xue Wang 《Environmental science and pollution research international》2014,21(23):13625-13635
Using rare minnow (Gobiocypris rarus) at early-life stages as experimental models, the developmental toxicity of five widely used triazole fungicides (myclobutanil, fluconazole, flusilazole, triflumizole, and epoxiconazole) were investigated following exposure to 1–15 mg/L for 72 h. Meanwhile, morphological parameters (body length, body weight, and heart rate), enzyme activities (superoxide dismutase (SOD), glutathione S-transferase (GST), adenosine triphosphatase (ATPase), and acetyl cholinesterase (AChE)), and mRNA levels (hsp70, mstn, mt, apaf1, vezf1, and cyp1a) were also recorded following exposure to 0.2, 1.0, and 5.0 mg/L for 72 h. Results indicated that increased malformation and mortality, decreased body length, body weight, and heart rate provide a concentration-dependent pattern; values of 72 h LC50 (median lethal concentration) and EC50 (median effective concentration) ranged from 3 to 12 mg/L. Most importantly, the results of the present study suggest that even at the lowest concentration, 0.2 mg/L, five triazole fungicides also caused notable changes in enzyme activities and mRNA levels. Overall, the present study points out that those five triazole fungicides are highly toxic to the early development of G. rarus embryos. The information presented in this study will be helpful in better understanding the toxicity induced by triazole fungicides in fish embryos. 相似文献
635.
为了对废聚苯乙烯泡沫塑料(WPS)资源化利用,通过对WPS进行催化裂解的方法,研究了催化剂种类和裂解温度对裂解时间、裂解油产率、苯乙烯回收率以及裂解油纯度的影响。研究结果表明,催化剂种类和裂解温度对裂解反应有着重要影响。裂解温度升高,裂解油产率提高,裂解时间缩短,但苯乙烯选择性下降;低于380 ℃时,氧化钙的裂解油产率和裂解时间优于氧化铝和氯化铝,但苯乙烯的选择性劣于氧化铝和氯化铝;高于400 ℃时,氯化铝、氧化铝和氧化钙的催化活性接近。在实验条件下,WPS催化裂解的最佳催化剂为氯化铝,380 ℃下的裂解时间为25 min,裂解油产率为85.48%,裂解油中苯乙烯含量为80.66%(w),且副产物较少。 相似文献
636.
Wenwen Gong Xinhui Liu Li Tao Wei Xue Wenjun Fu Dengmiao Cheng 《Environmental science and pollution research international》2014,21(9):6162-6169
In this paper, three types of black carbons (BCs) named R-BC, W-BC, and C-BC were derived from rice straw ashes, wheat straw ashes, and corn straw ashes, respectively. Under room temperature and in an anaerobic aqueous solution, these three types of BCs could catalyze the reduction of nitrobenzene (NB) by sulfides rather than only act as the superabsorbent. The catalytic activities of BCs derived from different crop-residue ashes were very different and in the order of R-BC > W-BC > C-BC, since the reaction rate constants (k obs) of NB with the BCs in the presence of 3 mM sulfides were 0.0186, 0.0063, and 0.0051 h?1, respectively. The key catalytic active sites for NB reduction were evaluated, with four types of modified BCs and two types of tailored graphite as the model catalysts. The results indicated that BCs probably had two types of active sites for NB reduction, the microscopic graphene moieties and the surface oxygen functional groups. Since the sulfides and BCs often coexist in the environment, this BC-catalyzed reduction technology of NACs may be applied as an in situ remediation technique without the need for reagent addition. 相似文献
637.
使用常见的工业材料:玻璃、铝片和镍网为载体,苯胺(Ani)作为氮掺杂剂,通过溶胶-凝胶法,制备了不同材料负载Ani/TiO2,并研究其在降解以酸性品红模拟的印染废水的光催化氧化性能。结果表明,玻璃、铝片和镍网负载Ani/TiO2最佳N/Ti值分别为0.250、0.040和0.040,并验证了N掺杂TiO2在日光利用方面的优势,提高了光催化剂的实际应用性;最佳pH值均为6~8;最佳处理初始浓度分别为10、12和12 mg/L;其光催化活性都会随着溶液深度的增加而降低;氧化剂硝酸铁的最佳投加浓度均为0.5×10-5到1.0×10-5mol/L;综合来看,玻璃负载Ani/TiO2的活性最高,铝片负载Ani/TiO2次之,镍网负载Ani/TiO2最差。 相似文献
638.
采用液相浸渍沉淀法制备AgI-BiOI/ZSM-5异质结催化剂,通过X-射线衍射(XRD)、紫外-可见光漫反射光谱(DRS)、扫描电镜(SEM)和交流阻抗(EIS)等表征技术对样品进行表征分析,研究AgI-BiOI/ZSM-5催化剂在可见光条件(λ> 420 nm)下催化氧化NO的可行性及异质结催化剂的稳定性.研究结果表明,所制备的AgI-BiOI/ZSM-5催化剂在可见光下催化氧化NO的效率达到90%,表现出良好的催化活性,而且AgI-BiOI/ZSM-5在反复使用5次后其催化活性基本保持不变.EIS测试结果表明,AgI-BiOI/ZSM-5异质结的形成有利于光生电子和空穴的分离,从而提高了AgI-BiOI/ZSM-5的催化活性和稳定性. 相似文献
639.
利用碳酸钡对蜂窝煤渣进行改性,通过粉末X射线衍射光谱(XRD)和扫描电镜(SEM)对改性前后蜂窝煤渣的物质组成和形貌进行表征,研究了改性蜂窝煤渣吸附Cr(Ⅵ)的动力学和热力学性能。实验结果表明,改性蜂窝煤渣对Cr(Ⅵ)具有良好的吸附能力,吸附过程符合准二级吸附动力学模型。分别用Langmuir、Freundlich、D-R和Tempkin等4种吸附等温线模型对实验数据进行拟合,Langmuir方程拟合效果最好,25、35和45℃下的饱和吸附量分别为2.985、2.562和2.630 mg/g。D-R和Tempkin模型研究表明,吸附过程属于物理吸附。热力学研究表明,改性蜂窝煤渣对Cr(Ⅵ)的吸附是一个自发的、放热过程。 相似文献
640.
通过甲醛与茶渣中多酚类组分的反应制备了多酚原位固化茶渣吸附材料,并将其用于对水中Cr(Ⅵ)的吸附。表征结果显示:茶渣多酚的原位固化提高了其热稳定性,同时对茶渣粒料起到了修补增强作用。固化茶渣对Cr(Ⅵ)的吸附量随溶液pH的减小而增大。在吸附温度303 K、初始Cr(Ⅵ)质量浓度60 mg/L、吸附剂投加量1.0 g/L、吸附时间300 min、溶液pH为2的条件下,固化茶渣对Cr(Ⅵ)的吸附量为56.56 mg/g,去除率达94.3%。固化茶渣对Cr(Ⅵ)的吸附符合Langmuir等温吸附模型和准二级动力学方程,吸附是一个自发的、吸热过程,303,318,333 K下的Langmuir饱和吸附量分别为83.26,107.64,129.20 mg/g。 相似文献